1. Field of the Invention
The present invention relates to a multilayer noise filter and, more particularly, to a multilayer noise filter which is constructed to eliminate and remove noises which are produced by high-frequency electronic equipment.
2. Description of Related Art
An example of a conventional multilayer noise filter is shown in FIG. 5. A conventional multilayer noise filter 41 includes inductor assemblies 42 and 43 which are constructed by stacking a plurality of coiled conductors and insulator layers, and a capacitor assembly 44 located between the inductor assemblies 42, 43. FIG. 5 schematically shows coils 51 and 52, which have been constructed by electrically connecting a plurality of coiled conductors, in the inductor assemblies 42 and 43, respectively. The axial direction of the coils 51 and 52, and the stacking direction of the inductor assemblies 42 and 43 and the capacitor assembly 44 are perpendicular relative to the external input and output electrodes 45 and 46, respectively, to reduce stray capacitance to thereby improve the insertion loss characteristic within a high-frequency region. One end of a capacitor conductor 55 of the capacitor assembly 44 is connected to a repeater electrode 48 and one end of a capacitor conductor 56 is connected to an external ground electrode 47. The coils 51 and 52 are electrically connected to each other via the repeater electrode 48.
FIG. 6 is an electric equivalent circuit diagram of the noise filter 41.
The conventional noise filter 41 experiences a problem in that the signal waveforms output from the noise filter 41 incur overshoots or other types of distortion due to impedance mismatching or resonance relative to a printed circuit board or other substrate on which the noise filter 41 is mounted. To control such distortions, it has been necessary to provide a damping resistor, which is separate from the filter, near the filter and electrically connect the damping resistor to the noise filter 41. The addition of the damping resistor requires extra mounting space on the printed circuit board or substrate upon which the noise filter is mounted and also requires extra assembly steps to mount and electrically connect the damping resistor thereby increasing the time, cost and difficulty of filter assembly process.